In series circuit, Req = R₁ + R₂ + R₃ + ···
In parallel circuit, 
<h3>Q7.</h3>
total resistance in the upper branch = R₂ + R₃ = R₂ + 2


R₂ + 2 = 12
R₂ = 10Ω
<h3>Q8.</h3>


Req = 1.7Ω
Answer:
Electric current.
Explanation:
The energy result from electric current resulting from potential differences between terminals which form an Electric circuit. This energy could come from different sources like chemical, wind, light
An electric circuit is one where there is movement of electrons;this electrons acquire charge which is energy. The electrons flow due to a potential difference; you have heard water flows from a higher position to a lower one freely. The highest height is said to be at higher potential and the lower point low potential.
So it's the same with electrons.
The formular for energy on charge is Q= I × t where I is electric current and t is time.
Given:
Gasoline pumping rate, R = 5.64 x 10⁻² kg/s
Density of gasoline, D = 735 kg/m³
Radius of fuel line, r = 3.43 x 10⁻³ m
Calculate the cross sectional area of the fuel line.
A = πr² = π(3.43 x 10⁻³ m)² = 3.6961 x 10⁻⁵ m²
Let v = speed of pumping the gasoline, m/s
Then the mass flow rate is
M = AvD = (3.6961 x 10⁻⁵ m²)*(v m/s)*(735 kg/m³) = 0.027166v kg/s
The gasoline pumping rate is given as 5.64 x 10⁻² kg/s, therefore
0.027166v = 0.0564
v = 2.076 m/s
Answer: 2.076 m/s
The gasoline moves through the fuel line at 2.076 m/s.
Ruby, a variety of the mineral corundum is in the trigonal crystal system, with hexagonal scalenohedra crystals